The invention relates to a film packing for a pasty substance, in particular an adhesive, sealing and/or forming masses or other age-hardening substances.
Pasty substances are normally marketed in disposable packings which are inserted into application devices such that they can be applied. In some cases the disposable packings are configured as rigid cartridges having a movable bottom which is moved, like a piston, into the cylindrical housing of the cartridge to discharge the pasty substance. Due to the relatively large amount of packing material to be disposed of, flexible disposable packings in the form of film tube bags are frequently used. Said film tube packings are made of a metal or plastic film tube which is tied together by clips at its two ends. Such a film tube bag is inserted into the cylindrical chamber of an applicator which comprises an outlet piece at one end of the cylindrical chamber. A stamp-type plate of the applicator is moved into the other end of the cylindrical chamber, which plate exerts a pressure onto the film tube bag and the pasty substance contained therein so that said substance is discharged through a passage opening in the end of the film tube bag facing the outlet piece and leaves the applicator through said outlet piece. Film packings of the type described above are e.g. known from DE-U-296 17 654, DE-U-296 13 945, EP-A-0 863 088 and EP-A-0 653 362.
The known film packings have substantially proved successful in practical applications. Problems may arise concerning the sealing of the film tube bag front end facing the outlet piece within the cylindrical chamber of the applicator. Said sealing of the end is realized in DE-U-296 17 654 and DE-U-296 13 945 by means of an O-ring seal arranged at the end in a cover element covering one end of the film tube bag. This type of sealing requires that the cover portion is permanently pressed at sufficient force against the end of the cylindrical chamber carrying the outlet piece. This is not adequately ensured at least in those phases in which the film tube bag is located inside the applicator and no pressure is exerted on the film tube bag.
From EP-A-0 607 609 an applicator is known where the components to be applied are inside a film tube bag. Said components are fed through a headpiece to an outlet nozzle. The headpiece is anchored to a cylindrical container wall by means of a screw cap. Further the headpiece is sealed towards the cylindrical container wall via a sealing ring. Said sealing ring is not attached to the film tube bag. Further said sealing ring is effective only in the screwed-together condition of the applicator and is not effective with regard to the screw cap.
Further, EP-A-0 693 437 describes an applicator for two components each packed in a foil tube wherein a headpiece is arranged on each foil tube, the headpiece comprising a central outlet piece. Both outlet pieces extend into the ends of channels of a counter-part part and are sealed towards the channels via an external sealing ring.
In EP-A-0 863 088 and EP-A-0 653 362, it is described that one end of the film tube bag is permanently attached to a cap comprising an outlet piece. Said cap and its outlet piece are then arranged at the front end of the cylindrical chamber of the applicator. Thus the cap forms part of the film packing and must be disposed of together with the film packing, which is expensive because of the relatively large amount of material used for the cap.
It is an object of the invention to provide a film packing having an improved sealing on said one end side of the film packing.
According to the invention, the above object is achieved by means of a film packing for a pasty substance, comprising
a film tube bag having a peripheral wall and two ends, and
a cover portion fastened to one of the two ends of the film tube bag,
the cover portion comprising an end face having a passage opening for the passage of pasty substance from the opened film tube bag, a peripheral face joining the end face, and a sealing element abutting to a receiving headpiece attachable to the end of the film tube bag carrying the cover portion,
the receiving headpiece surrounding at least the end face and the peripheral face of the cover portion and comprises an outlet piece which is in fluid connection with the passage opening of the cover portion when the receiving headpiece is attached.
According to the invention, the sealing element is arranged on the peripheral face and/or in the transition area between end face and peripheral face of the cover portion of said film packing. The film packing according to the present invention thus possesses a radially acting sealing towards the applicator.
The film packing according to the invention is provided with a film tube bag comprising a peripheral wall and two end faces where the film tube bag is tied together or closed in any other way. One of said two ends carries a cover portion which may be configured as a ring or a disk. Said cover portion comprises an end face and a peripheral face adjoining said end face. Said cover portion and at least a portion of the film tube bag end connected with the cover portion are inserted into a receiving headpiece of an applicator, said receiving headpiece being adapted to be positioned at one of the two ends of a cylindrical pressure chamber of the applicator. Said receiving headpiece is provided with an outlet piece communicating with a passage opening of the cover portion when the receiving headpiece is attached.
To discharge a pasty substance from the film tube bag according to the invention with the aid of an applicator comprising a stamp-type pressure plate, the film tube bag is opened in an area of its one end being in alignment with the passage opening of the cover portion, so that the pasty substance can leave the open film tube bag through the passage opening and the outlet piece being in fluid connection with the latter.
Sealing between the end of the film tube bag carrying the cover portion and the applicator is effected via a radially arranged sealing element located on the peripheral face of the cover portion and/or in the transition area between end face and peripheral face. When the film tube bag is in use, said sealing element rests against the receiving headpiece and/or the cylindrical pressure chamber of the applicator. The sealing element remains in sealing contact with the receiving headpiece and/or the cylindrical pressure chamber irrespective of the pressure exerted by the pressure plate onto the film tube bag. Thus, a reliable sealing is always ensured from the beginning of an application process. In this way the applicator can be effectively prevented from becoming soiled with pasty substance. Only the film tube bag and the cover portion must be disposed of; the receiving headpiece can be reused.
The radially arranged sealing element according to the invention may have different configurations. Appropriately a sealing ring (in particular an O-ring) is used as sealing element, which is arranged in a receiving groove arranged in the peripheral face of the cover portion. Besides a round profile a flat profile may also be used as cross-section of the sealing ring. The sealing element may also be configured as an elastic sealing lip integrally formed with the cover portion. Said sealing lip rests from the inside against the receiving headpiece or the cylindrical pressure chamber of the applicator thus sealing it. A further alternative is to configure the seal as labyrinth seal between the cover portion and the applicator (receiving headpiece and/or cylindrical pressure chamber). Such a labyrinth seal can e.g. be realized by the cover portion comprising on its peripheral face at least one and preferably a plurality of annular projections. In a preferred development of the invention the cover portion comprises on its peripheral edge a shoulder area within which the cover portion surrounds the transition area between the end and the peripheral wall of the film tube bag. Such a shoulder-type structure of the cover portion allows for improved guiding of the film tube bag and positioning it in the receiving head piece or the cylindrical pressure chamber of the applicator. When the cover portion is of substantially flat configuration, there is sufficient room for attaching and arranging the sealing element within the surrounding edge of the cover portion.
An alternative to the embodiment of the cover portion described above provides for the cover portion being substantially configured as a disk which does not comprise a projecting surrounding edge and in whose peripheral face defined by the thickness of the disk the sealing element is arranged.
Appropriately the cover portion is configured as an annular portion. This offers advantages with regard to the reduced amount of material required for the cover portion. The annular portion surrounds the film tube bag in the transition area between one end and the peripheral wall. In the remaining area the end of the film tube bag is exposed. Thus the annular portion defines a central passage opening within which the connection with the outlet piece can be effected even if the latter is eccentrically arranged, with the connection between the eccentric outlet piece and the passage opening being of a substantially straight configuration, i.e. without considerable deflections which may lead to increased flow resistances. If however a disk-type cover portion is used instead of an annular cover portion and if the receiving headpiece comprises an eccentrically arranged outlet piece, care must be taken during insertion of the film tube bag into the pressure chamber of the applicator that a certain twisting alignment of the film tube bag is observed in order to utilize, in the case of eccentric arrangement of the outlet piece, the advantages of a substantially straight flow connection between the passage opening and the outlet piece. However this can be realized at relatively small expenditure by providing the cover portion with engagement projections and recesses cooperating with corresponding engagement recesses/projections of the receiving headpiece, thus allowing insertion of the cover portion into the receiving headpiece in only one position (coding).
In a preferred embodiment of the invention it is provided that the cover part comprises, within its area flatly resting against the end of the film tube bag, a (central) projection acting upon the tied-together section of the film tube bag and pressing said tied-together section into the end of the film tube bag. This allows more material to be taken out of the film tube bag since pressure is not only applied to the bag from the pressure plate side but also through the central projection which moves the tied-together section of the film tube bag in an inward direction. Within the central projection a recess for a closing clip of the film tube bag may be arranged by means of which the film tube bag is tied together and sealed.
Even in the case of an annular configuration of the cover portion additional pressure can be applied by the central projection described above to the end of the film tube bag. In this case the central projection is not located on the cover portion but on the receiving headpiece, with said central projection extending through the outlet piece defined by the ring and acting upon the film tube bag. This configuration further presents the advantage that owing to the central impression of the film tube bag the latter arches on the peripheral edge of its end, which facilitates automatic opening of the film tube bag by means of a piercing pin or a similar tool of the receiving headpiece.
According to an advantageous embodiment of the invention, a locking means is provided to connect the cover portion to the receiving headpiece for securing the cover portion against undesired detachment from the receiving headpiece. This well-aimed locking of the cover portion to the receiving headpiece facilitates the removal of a film tube bag from the applicator. Without this temporary connection, the receiving headpiece would be removed from the pressure chamber of the applicator, with the film tube bag with its cover portion remaining in the cylindrical pressure chamber. To make it possible, in this situation, to remove the film tube bag from the cylindrical pressure chamber, the cover portion would have to be grasped by hand to thus pull out the film tube bag from the pressure chamber. By contrast, it is easier to remove the film tube bag from the pressure chamber by grasping the receiving headpiece. According to the invention, this is performed by use of the locking means between the cover portion and the receiving headpiece. Within the scope of the invention, this feature has an importance of its own. Particularly, this feature can be realized in the film packing of the invention without necessarily also realizing the radial sealing.
The locking device between the receiving headpiece and the cover portion is preferably realized by elements optionally being adapted to be disengaged and appropriately configured as a snapping device. Said snapping device comprises in particular complementary snapping projections and snap-in recesses arranged on the cover portion and the receiving headpiece. Said snapping projections and snap-in recesses are attached to e.g. elastic studs in particular of the cover portion. Generally one such elastic stud is sufficient; for reasons of ease of handling it is, however, appropriate to provide two studs arranged diametrically opposite each other on the cover portion. Said studs extend transversely to the end face of the cover portion and are accessible from outside when the cover portion is inserted into the receiving headpiece so that the cover portion can be released from the receiving headpiece when a force is applied from outside on the at least one stud.
The locking of the film tube bags via their cover element on the receiving headpiece can also be performed in a preliminary position in which a piercing pin arranged in the receiving headpiece has not yet perforated the film tube bag. Only when the film tube bag, held locked on the receiving headpiece, is moved farther into the receiving headpiece, the piercing of the film tube bag will be effected. Also in this position, the cover element of the film tube bags is locked on the receiving headpiece. The snap-on connection between the receiving headpiece and the film tube bag offers the advantage that both components can be distributed together and that the user can open the film tube bag by a defined cooperating movement of both components. This is particularly advantageous if the receiving headpiece as well as the film tube bag are designed as disposable articles.
Alternative embodiments of the locking device are a bayonet catch or a thread. The locking device may be realized, by way of alternative to a releasable positive locking connection, by means of a releasable non-positive locking connection configured as a frictional connection.
To facilitate movement of the cover portion with the film tube bag from the preliminary position to the final position on the receiving headpiece it is advantageous when the snapping action does not present too large a resistance. However this is disadvantageous to a certain degree during the transport of the film tube bag preliminarily positioned on the receiving headpiece. During the transport, care should be taken that the film tube bag does not accidentally move from the preliminary position in the direction of the final position and further into the receiving headpiece since this would result in an unintentional opening of the film tube bag and thus discharge of the material contained therein.
To solve the aforementioned problem it is proposed, according to an alternative embodiment of the invention, to employ a film tube packing according to claim 1 where, according to the invention, a stopping element is arranged on the receiving headpiece, the stopping element being movable between a stopping position, to prevent unintentional movement of the film tube bag from the preliminary position in the direction of the final position, and a release position in which the film tube bag can be moved into the final position. Said stopping element may have various configurations and e.g. lock the cover portion to the receiving headpiece such that the cover portion cannot be moved from the preliminary position either in the direction of the final position or in the opposite direction. However with regard to the considerations and solutions forming the basis of the present invention it is sufficient when the stopping element merely ensures that the film tube bag is not movable towards the final position. Thus it e.g. suffices when the stopping element in its stopping position extends into the space between the cover portion of the film tube packing and the receiving headpiece.
The stopping element, too, could unintentionally move from its stopping position into its release position. This is appropriately prevented by locking or blocking the stopping element to protect it against unintentional movement into the release position. For this purpose e.g. a frictional or positive connection of the stopping element with the receiving headpiece or the cover portion is sufficient.
As described above, the receiving headpiece comprises an outlet piece. It would be the obvious approach to shift the stopping element from the end averted from the film tube bag into the outlet piece wherein the stopping element extends over the other end of the outlet piece and acts as a stop to delimit the movement of the cover portion and the film tube bag towards the outlet piece. In this embodiment of the invention the stopping element is twistable between a first and a second twisting position in the outlet piece. In the first twisting position, the stopping element is in its stop position. In the first twisting position it is advantageous when the stopping element is protected against unintentional axial movement out of the outlet piece by being locked in the outlet piece or to the cap and/or the cover portion. This can e.g. be realized by cooperating locking or stopping faces on the stopping element on the one hand and on the outlet piece, the receiving headpiece and/or the cover portion on the other hand. By twisting the stopping element from the first twisting position into the second twisting position the stopping element is unlocked from the receiving headpiece; now the stopping element can be pulled out of the outlet piece and moved into its release position in which the cover portion and the film tube bag fastened thereto can be moved towards the outlet piece and thus towards the piercing pin.
In the variant of the invention described above the stopping element appropriately has the form of a pin or a bolt. At that end of the stopping element which extends from the end averted from the film tube bag when the stopping element is in the outlet piece, the stopping element is configured such that it allows said end of the stopping element to be manually grasped and twisted.
The above development of the film tube packing according to the invention comprising a stopping element as transport protection means of the preliminarily positioned film tube bag is realizable for receiving headpieces whose outlet pieces exceed a certain minimum diameter. If however the diameter of the outlet piece is too small, the stopping element must be relatively thin. This leads to stability problems and problems with regard to locking the stopping element on the receiving headpiece.
Thus, it is advantageous when the stopping element, in its stopping position, extends transversally through the space between the cover portion and the end wall of the receiving headpiece. This can e.g. be effected by the stopping element, in its stopping position, extending through an opening in the peripheral edge on the end wall of the receiving headpiece. With regard to the positional stability of the stopping element it is appropriate when the stopping element extends through two openings arranged opposite each other on the edge. Said two openings are preferably located on a mathematical straight line extending as a secant to the receiving headpiece when the latter is substantially configured as a cylindrical cap. The stopping element, which is in particular of a pin or bolt form, is appropriately adapted to be locked on the receiving headpiece to protect it against unintentional slipping out of the opening/openings of the receiving headpiece. Locking is preferably realized by means of a locking projection which, in a first twisting position of the stopping element, is inserted into a snap-in recess on the receiving headpiece and, in a second twisting position, is disengaged from this snap-in recess with the stopping element being adapted to be axially moved out of said space in this twisting position.
Thus the stopping element forms a transport protection means for the film tube packing when the film tube bag plus the cover portion are preliminarily positioned on the receiving headpiece. This improves handling of the film tube packing according to the invention.
In a preferred development of the invention it is further provided that the passage opening of the cover part is at least partially surrounded by a sealing projection, or the receiving headpiece comprises a sealing projection which extends through the passage opening and may be of peripheral configuration. In the condition as used said sealing projection rests against the film tube bag. Within the area defined by the sealing projection, the film tube bag is open when the pasty substance is discharged from the bag. As mentioned above, the film tube bag can be opened by means of a piercing pin or a similar piercing tool arranged on the receiving headpiece. The lip-type sealing projection seals the area around the opening in the film tube bag, which reduces the risk that the pasty substance leaving the film tube bag smears the inner face of the receiving headpiece.
The arrangement of the piercing tool on the receiving headpiece separated from the film tube bag offers the advantage that the film tube bag is opened only when the receiving headpiece is placed onto the cover portion of the film packing. Thus the opening process takes place after the film packing has been inserted into the pressure chamber of the dispenser or the applicator and only when the user deliberately places the receiving headpiece onto the cover portion which rests on one end of the pressure chamber of the dispenser or the applicator.
The above receiving headpiece and its features, in particular a central projection on the inside facing the end of the film tube bag with the snap-in recess for a closing clip arranged at the end of the film tube bag, are to be considered themselves as patentable within the scope of this description.